that is my short script: scalar smpl_size=25 nulldata smpl_size scalar n = $nobs scalar nr=100 series betas = NA loop i=1..nr --quiet series x_$i=randgen(u,0,100) series v_$i=randgen(n,0,1) series y_$i=x_$i+v_$i ols y_$i x_$i --quiet betas[$i]=$coeff endloop *delete x_* y_* v_** series betas_norm=sqrt(n)*(betas-1) And deleting is not performed, "because the variables are in use". Do you know a solution?